Adds support for multi-region

Change-Id: Ib85fe7cb375692b04aca4c46f61ba7e1fbfa501b
Implements: blueprint multi-region
Revert "Add missing config option os_auth_url"

This reverts commit 524bbed05ce9de0bd711aa18c35afa4476978404.

Change-Id: I0dc3ec7a55cb65bd2a5ff76f32b3d99f8962597b
Merge "Adds support for multi-region"
Merge branch 'master' of https://github.com/openstack-dev/devstack